With reference to people or animals: close together and facing in the same direction; abreast. Also with with: next to, beside.

cheek by cheek: side by side, alongside; in close or intimate proximity. Cf. cheek to cheek, adv. adj.n., cheek by jowl, adv.

hand by hand: = hand in hand, adv. Formerly also: = hand to hand, adv. (obsolete).

In (or into) a position in which the intervening space is closed up, so that there is no interval; in… Of the mutual proximity of two or more…

hand for hand = hand in hand, adv.; (also) = hand to hand, adv. Obsolete.

Phrases. shoulder to shoulder: lit. of soldiers, so as to shoulder one another, in close conflict; also, in rank, in close formation; hence figurative…

†at (the) eye's end: close at hand. Obsolete.

In various phrases. knee by knee, side by side and close together; knee to knee, = knee by knee; also, facing each other with the knees touching.

corps à corps/kɔr a kɔr/, body to body; in immediate contact; spec. in Fencing (see quot. 1910). Also transferred and figurative.